Qi Su1, Qing Wu1, Kun Chen1, Jingjing Wang1, Ammar Sarwar1, Yanmin Zhang2. 1. School of Pharmacy, Health Science Center, Shaanxi Province, Xi'an Jiaotong University, No. 76, Yanta West Street, #54, Xi'an, 710061, People's Republic of China. 2. School of Pharmacy, Health Science Center, Shaanxi Province, Xi'an Jiaotong University, No. 76, Yanta West Street, #54, Xi'an, 710061, People's Republic of China. zhang2008@xjtu.edu.cn.
Abstract
BACKGROUND: Female breast cancer has become the most commonly diagnosed cancer worldwide. As a tumor suppressor, estrogen receptor β (ERβ) can be potentially targeted for breast cancer therapy. METHODS AND RESULTS: TAD1822-7 was evaluated for ERβ-mediated autophagy and cell death using cell proliferation assay, Annexin V/PI staining, immunofluorescence, western blotting, ERβ siRNA, ERβ plasmid transfection and hypoxia cell models. TAD1822-7 upregulated ERβ causing cell death and induced mitochondrial dysfunction and autophagy companied with mitochondrial located ERβ. Enhanced levels of microtubule associated protein1 light chain 3 (LC3)-II and p62/SQSTM1 (p62) indicated that TAD1822-7 blocked the late-stage autolysosome formation, leading to cell death. Mechanistically, TAD1822-7-induced cell death was mediated by phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathways. Moreover, TAD1822-7 modulated hypoxia inducible factor (HIF) functions and autophagy via the inhibition of HIF-1β in the context of hypoxia-induced autophagy. ERβ overexpression and ERβ agonist showed similar effects, whereas ERβ siRNA abrogated TAD1822-7-induced cell death, the inhibition of PI3K/AKT pathway and autophagy. The involvement of PI3K/AKT pathway and autophagy was also demonstrated in TAD1822-7-treated hypoxic breast cancer cells. CONCLUSIONS: These findings provide new insight into the mechanism underlying the inhibitory effects of TAD1822-7 via ERβ-mediated pathways in breast cancer cells.
BACKGROUND: Female breast cancer has become the most commonly diagnosed cancer worldwide. As a tumor suppressor, estrogen receptor β (ERβ) can be potentially targeted for breast cancer therapy. METHODS AND RESULTS: TAD1822-7 was evaluated for ERβ-mediated autophagy and cell death using cell proliferation assay, Annexin V/PI staining, immunofluorescence, western blotting, ERβ siRNA, ERβ plasmid transfection and hypoxia cell models. TAD1822-7 upregulated ERβ causing cell death and induced mitochondrial dysfunction and autophagy companied with mitochondrial located ERβ. Enhanced levels of microtubule associated protein1 light chain 3 (LC3)-II and p62/SQSTM1 (p62) indicated that TAD1822-7 blocked the late-stage autolysosome formation, leading to cell death. Mechanistically, TAD1822-7-induced cell death was mediated by phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathways. Moreover, TAD1822-7 modulated hypoxia inducible factor (HIF) functions and autophagy via the inhibition of HIF-1β in the context of hypoxia-induced autophagy. ERβ overexpression and ERβ agonist showed similar effects, whereas ERβ siRNA abrogated TAD1822-7-induced cell death, the inhibition of PI3K/AKT pathway and autophagy. The involvement of PI3K/AKT pathway and autophagy was also demonstrated in TAD1822-7-treated hypoxic breast cancer cells. CONCLUSIONS: These findings provide new insight into the mechanism underlying the inhibitory effects of TAD1822-7 via ERβ-mediated pathways in breast cancer cells.
Authors: Lorenzo Galluzzi; Federico Pietrocola; José Manuel Bravo-San Pedro; Ravi K Amaravadi; Eric H Baehrecke; Francesco Cecconi; Patrice Codogno; Jayanta Debnath; David A Gewirtz; Vassiliki Karantza; Alec Kimmelman; Sharad Kumar; Beth Levine; Maria Chiara Maiuri; Seamus J Martin; Josef Penninger; Mauro Piacentini; David C Rubinsztein; Hans-Uwe Simon; Anne Simonsen; Andrew M Thorburn; Guillermo Velasco; Kevin M Ryan; Guido Kroemer Journal: EMBO J Date: 2015-02-23 Impact factor: 11.598